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1.
The microbiota of the Amazon River basin has been little studied. We compared the structure of bacterial communities of the Solim?es and Negro Rivers, the main Amazon River tributaries, based on analysis of 16S rRNA gene sequences. Water was sampled with a 3-L Van Dorn collection bottle; samples were collected at nine different points/depths totaling 27 L of water from each river. Total DNA was extracted from biomass retained by a 0.22-μm filter after sequential filtration of the water through 0.8- and 0.22-μm filters. The 16S rRNA gene was amplified by PCR, cloned and sequenced, and the sequences were analyzed with the PHYLIP and DOTUR programs to obtain the operational taxonomic units (OTUs) and to calculate the diversity and richness indices using the SPADE program. Taxonomic affiliation was determined using the naive Bayesian rRNA Classifier of the RDP II (Ribosomal Database Project). We recovered 158 sequences from the Solim?es River grouped into 103 OTUs, and 197 sequences from the Negro River library grouped into 90 OTUs by the DOTUR program. The Solim?es River was found to have a greater diversity of bacterial genera, and greater estimated richness of 446 OTUs, compared with 242 OTUs from the Negro River, as calculated by ACE estimator. The Negro River has less bacterial diversity, but more 16S rRNA gene sequences belonging to the bacterial genus Polynucleobacter were detected; 56 sequences from this genus were found (about 30% of the total sequences). We suggest that a more in-depth investigation be made to elucidate the role played by these bacteria in the river environment. These differences in bacterial diversity between Solim?es and Negro Rivers could be explained by differences in organic matter content and pH of the rivers.  相似文献   

2.
Eighteen core samples from PETROBRAS well 1-JD-1-AM (Jandiatuba area, Solimões Basin, northwestern Brazil) have been studied for miospores. Fifty-three species are identified. This assemblage is tentatively correlated with the Z Phylozone of the BZ Oppel Zone (Steemans, P., 1989. Palynostratigraphie de l'Eodévonien dans l'ouest de l'Europe. Professional Paper. Mémoires Explicatifs pour les Cartes Géologiques and Minéralogiques de la Belgique, 27, pp. 453.), dated late Lochkovian. This is in accordance with previous age determinations based on chitinozoans and acritarchs. Numerous representatives of the miospore genus Dictyotriletes are observed. These enable recognition of the Dictyotriletes emsiensis morphon, an informal classification unit which includes Dictyotriletes granulatus, D. emsiensis, Dictyotriletes cf. subgranifer, specimens previously misassigned to D. subgranifer and some Dictyotriletes spp. provisionally left in open nomenclature. Since all intermediate forms from typical D. granulatus to typical D. emsiensis coexist, it is currently difficult to determine the base of “E” Interval Biozone in South America as originally defined in Western Europe. It is suggested, therefore, that the base of the “Ems” Biozone defined in Brazil cannot be correlated with the base of the “E” Biozone. Instead, it should be included in an interval of uncertainty ranging from the European “Si” to “E” Biozones. Indeed, the underlying “NsZ” Biozone from South America contains species not known below the “Si” Biozone. Here, the D. emsiensis morphon Assemblage Zone is erected, which may be coeval with the “N” through “E” Biozones of Western Europe. The PISA palynoflora from the Paraná Basin is also attributed to this new biozone. However, in the absence of species observed in the “BZ” Biozone (and also in the Solimões Basin), the PISA assemblage could be somewhat older than that of well 1-JD-1-AM.  相似文献   

3.
We report here a new fossil primate from the late Miocene of Brazil. The material consists of a lower first molar and a maxilla with P3-4. The fossils were collected in the Solim?es Formation at the locality of Patos, upper Acre River, Acre State, Brazil. The locality is assigned to the Huayquerian South American Land Mammal Age based on faunal content (late Miocene; dated to between 9 and 6 Ma). The new material is the oldest known occurrence of fossil primates in Brazil and is recognized as a new genus and species, Solimoea acrensis. Solimoea is the oldest known member of the ateline subfamily, which includes the living genera Ateles, Lagothrix, and Brachyteles. By analogy with the molar structures and diets of extant platyrrhines, Solimoea primarily had a diet of fruit, perhaps similar to that of the spider monkey, Ateles. Two other primate teeth described previously from the same formation in Bolivia document the occurrence of alouattines and cebines. One of those specimens is a late Miocene representative of the middle Miocene Colombian genus Stirtonia. The other represents one of the largest known platyrrhine primates, for which is erected a new primate genus, Acrecebus fraileyi.  相似文献   

4.
Major collections of the ultramafic flora of Goiás, central Brazil, were made by Brooks and co-workers in 1988 and 1990. At the time of reports on this material in 1990–1992 much of it had been identified only tentatively and incompletely, but the area was clearly interesting for taxonomic and biogeochemical reasons. Further progress has been made but still only two-thirds of the specimens are identified at the species level. Following a third collection in early 2005, we now have 800 specimens from this area, with chemical analyses of all the plants and of more than 120 representative soil samples. New species have been found, e.g., in Paspalum (Poaceae) and Pterolepis (Melastomataceae). There is a need for more taxonomic work in genera such as Cnidoscolus (Euphorbiaceae), Lippia (Verbenaceae), Turnera and Piriqueta (Turneraceae), and Vellozia (Velloziaceae). Ni hyperaccumulation (>1,000 mg/kg in dry plant matter) has now been found in a total of 79 specimens, representing more than 30 different species. Notable Ni hyperaccumulators include Pfaffia sarcophylla (Amaranthaceae), species of Justicia, Lophostachys and Ruellia (Acanthaceae), Porophyllum (Asteraceae), several species of Lippia (Verbenaceae), Turnera and Piriqueta (Turneraceae), and a possibly new Cnidoscolus (Euphorbiaceae). Ni hyperaccumulation has not been found in plants of the outcrops of Morro Feio or Crominia-Mairipotaba; it seems to be confined to the extensive layered ultramafics of Barro Alto and the Macedo-Niquelandia areas. The distribution of Ni-values in the Brazilian plant collection is different from that found in the Mediterranean and California, where there is a clear distinction between accumulator and non-accumulator plants: in Brazil the distribution is more continuous, and median Ni concentrations are much greater. An ultramafic hill just north of Niquelandia deserves to be protected because of the presence there of many of the hyperaccumulators and species probably endemic to the Goiás ultramafics.  相似文献   

5.
Science is now studying biodiversity on a massive scale. These studies are occurring not just at the scale of larger plants and animals, but also at the scale of minute entities such as bacteria and viruses. This expansion has led to the development of a specific sub-field of “microbial diversity”. In this paper, I investigate how microbial diversity faces two of the classical issues encountered by the concept of “biodiversity”: the issues of defining the units of biodiversity and of choosing a mathematical measure of diversity. I also show that the extension of the scope of biodiversity to microbial entities such as viruses and many other not-clearly-alive entities raises yet another foundational issue: that of defining a “lower-limit” of biodiversity.  相似文献   

6.
The present study reports a collection of Amblyomma spp. ticks in birds from several areas of the state of São Paulo, Brazil. A total of 568 tick specimens (404 larvae, 164 nymphs) were collected from 261 bird specimens. From these ticks, 204 (36%) specimens (94 larvae, 110 nymphs) were reared to the adult stage, being identified as Amblyomma longirostre (94 larvae, 90 nymphs), Amblyomma calcaratum (13 nymphs), Amblyomma nodosum (2 nymphs), and Amblyomma cajennense (5 nymphs). Additionally, 39 larvae reared to the nymphal stage and 8 nymphs that died before reaching the adult stage were identified as A. longirostre according to peculiar characters inherent to the nymphal stage of this species: scutum elongate, and hypostome pointed. The remaining 271 larvae and 46 nymphs were identified as Amblyomma sp. Ticks were collected from 51 species of birds distributed in 22 bird families and 6 orders. The order Passeriformes constituted the vast majority of the records, comprising 253 (97%) out of the 261 infested birds. Subadults of A. longirostre were identified from 35 species of Passeriformes, comprising 11 families (Cardinalidae, Dendrocolaptidae, Fringillidae, Furnariidae, Parulidae, Pipridae, Thamnophilidae, Thraupidae, Turdidae, Tyrannidae, and Vireonidae), and from 1 species of a non-passerine bird, a puffbird (Bucconidae). Subadults of A. calcaratum were identified from 5 species of Passeriformes, comprising 5 families (Cardinalinae, Conopophagidae, Pipridae, Thamnophilidae and Turdidae). Subadults of A. nodosum were identified from 2 species of Passeriformes, comprising two bird families (Thamnophilidae and Pipridae). Subadults of A. cajennense were identified from 2 species of non-passerine birds, belonging to 2 different orders (Ciconiiformes: Threskiornithidae, and Gruiformes: Cariamidae). Birds were usually infested by few ticks (mean infestation of 2.2 ticks per bird; range: 1–16). Currently, 82 bird species are known to be infested by immature stages of A. longirostre, with the vast majority [74 (90%)] being Passeriformes. Our results showed that Passeriformes seems to be primary hosts for subadult stages of A. longirostre, A. calcaratum, and A. nodosum. However, arboreal passerine birds seem to be the most important hosts for A. longirostre whereas ground-feeding passerine birds seem to be the most important for both A. calcaratum and A. nodosum. In contrast, the parasitism of birds by subadults of A. cajennense has been restricted to non-passerine birds.  相似文献   

7.
The Lecythidaceae or Brazil Nut family are ubiquitous in non-flooded lowland forests of the Amazon, where they are indicative of well-preserved or little-disturbed habitats. A recent checklist of the Brazilian flora reported 10 genera and 119 species for that country, of which 104 are found in the Amazon region. However, the botanical knowledge in many regions of the country remains far from complete. This study aimed to analyze the diversity of Lecythidaceae in the upper Madeira River region in Rondônia, an area where botanical data is scarce. Lecythidaceae collections deposited in the CEN, INPA and RON herbaria were examined, and four field expeditions in the study area were carried out. For that region, we recorded 37 species of Lecythidaceae belonging to 7 genera: Eschweilera (21 species), Couratari (6), Cariniana (3), Gustavia (3), Allantoma (2), Bertholletia (1) and Lecythis (1). Among these species, five are listed as threatened in the IUCN Red List. The total number of species found in the upper Madeira River of Rondônia alone is higher than the 28 species reported to date for the entire state of Rondônia in the Brazilian Flora Checklist (Smith et al., 2015), and adds 13 new records of Lecythidaceae for the state. Considering that this study is restricted to the northern part of the state, our results suggest that the number of Lecythidaceae species in Rondônia is severely underestimated. Our findings highlight the need for more intensive floristic studies in the Amazon region, which should target areas that are botanically unexplored but have high biodiversity potential. Such studies will provide valuable information to support both taxonomic studies and species conservation assessments.  相似文献   

8.
The biological behaviour of 23 Trypanosoma cruzi isolates in Swiss mice was compared. Nineteen isolates were obtained from patients in the acute phase of Chagas disease (13), sylvatic reservoir hosts (Didelphis marsupialis) (3), and triatomine bugs (Rhodnius robustus) (3) from four regions of the State of Amazonas (AM). Four isolates were obtained from chronic chagasic patients in the State of Paraná (PR): three autochthones, and one allochthone from the State of Minas Gerais. Only one isolate was unable to infect the mice. The AM and PR isolates showed the largest number of significant differences from each other. The former had lower mean values in the pre-patent (5.4 days) and patent (4.6 days) periods (PP), with the parasitaemia (Pmax) reaching a peak of 9.9×10(4) blood trypomastigotes (BT)/mL of blood by the 7th day following inoculation. The AM isolates also had higher positivity to fresh-blood examination (FBE) (84.1%) compared to haemoculture (HC) (58.7%) and polymerase chain reaction (PCR) (33.3%), in addition to higher mortality (2.9%). The PR isolates had higher values for PP (18.5 days) and Pmax (99.9×10(4)BT/mL) as well as higher positivity to FBE (87.2%), HC (100%), and PCR (83.3%). The correlations between the biological behaviour of the T. cruzi isolates and the clinical and epidemiological characteristics of Chagas disease are discussed.  相似文献   

9.
AIMS: To investigate whether modifications in Yersinia pestis isolates from three plague foci from the state of Ceará, Brazil, had occurred over the years as a consequence of genetic adaptation to the environment. METHODS AND RESULTS: The isolates were studied with respect to susceptibility to antimicrobial drugs, plasmid and protein profiling, pigmentation on Congo red-agar plates, and the presence of some pathogenicity genes using PCR. Most of the expected virulence markers were detected in the cultures examined. There was no evidence of any alteration that could be associated with their origin (patients, rodents and fleas) or period of isolation (1971-1997). CONCLUSIONS, SIGNIFICANCE AND IMPACT OF THE STUDY: Phenotypic or genotypic changes were not detected in the cultures examined. However, the results obtained will serve as a reference to follow the evolution of Y. pestis in these foci.  相似文献   

10.
11.
Aspergillus flavus is a very important toxigenic fungus that produces aflatoxins, a group of extremely toxic substances to man and animals. Toxigenic fungi can grow in feed crops, such as maize, peanuts, and soybeans, being thus of high concern for public health. There are toxigenic and non-toxigenic A. flavus variants, but the necessary conditions for expressing the toxigenic potential are not fully understood. Therefore, we have studied total-DNA polymorphism from toxigenic and non toxigenic A. flavus strains isolated from maize crops and soil at two geographic locations, 300 km apart, in the Southeast region of Brazil. Total DNA from each A. flavus isolate was extracted and subjected to polymerase chain reaction amplification with five randomic primers through the RAPD (random amplified polymorphic DNA) technique. Phenetic and cladistic analyses of the data, based on bootstrap analyses, led us to conclude that RAPD was not suitable to discriminate toxigenic from non toxigenic strains. But the present results support the use of RAPD for strain characterization, especially for preliminary evaluation over extensive collections.  相似文献   

12.
Systematic Parasitology - Megalodoras uranoscopus (Eigenmann & Eigenmann) (Siluriformes, Doradidae) (the giant-talking catfish or the giant-raphael catfish), from the...  相似文献   

13.
The microbial community of artisanal corn fermentation called Chicha were isolated, purified and then identified using protein profile by Matrix Assisted Laser Desorption Ionization Time-of-Flight Mass Spectrometry (MALDI-TOF) and confirmed by partial ribosomal gene sequencing. Samples from Chicha beverage were chemically characterized by gas and liquid chromatography (HPLC and GC-MS). Aerobic mesophilic bacteria (AMB) (35.8% of total of isolated microorganisms), lactic acid bacteria (LAB) (21.6%) and yeast (42.6%) were identified. Species of the genera Klebsiella, Bacillus, Staphylococcus, Micrococcus, Enterobacter, and Weissella were identified. Rhodotorula mucilaginosa, Lodderomyces elongisporus, Candida metapsilosis, and C. bohicensis were the yeasts found. The LAB isolates detected were responsible for the high concentrations of lactic acid found during the fermentation process (1.2 g L??1), which is directly related to the decrease in pH values (from 6.95 to 3.70). Maltose was the main carbohydrate detected during corn fermentation (7.02 g L??1 with 36 h of fermentation). Ethanol was found in low concentrations (average 0.181 g L??1), making it possible to characterize the beverage as non-alcoholic. Twelve volatile compounds were identified by gas chromatography; belonging to the groups acids, alcohols aldehydes, acetate and others. MALDI-TOF was successfully used for identification of microbiota. Weissella confusa and W. cibaria were detected in the final product (after 36 h of fermentation), W. confusa is often classified as probiotic and deserve further application studies.  相似文献   

14.
Factors driving the species richness and distribution of bryophytes are poorly studied and not well understood, particularly in grasslands. We analysed the occurrence of bryophyte species and variation in species richness across 674 plots (0.5?m?×?0.5?m) in alvar vegetation (grassland on limestone pavement with thin or no soil) on Öland (Sweden) in relation to substrate characteristics and chemistry, inundation frequency, grazing pressure and geographical variables. We found 148 taxa, including 11 nationally red-listed ones. Species richness per plot was significantly associated with substrate type, positively associated with pH and grazing intensity, but negatively associated with soil depth. However, richness of species typical of, or restricted to, alvar habitats responded differently to richness of species more common in other habitats. Typical alvar species were favoured by high pH, shallow soil and low phosphate availability, while generalists preferred relatively low pH, higher phosphate availability and organic or mull soil types. Distance from the alvar margin had only weak effects. Concerning the effects on individual species and community composition, inundation frequency and pH were found to have the largest effects, although other factors (substrate type, soil depth, bare soil, bare stone, phosphate availability and grazing pressure) were more important for some individual species, stressing the importance of microsite variability and variability in management for regional species richness. From a conservation perspective, it is concluded that grazing is generally positive whilst factors increasing phosphate availability may disadvantage the typical alvar species, and proximity to the alvar margin is not a major problem.  相似文献   

15.
The present study was conducted to investigate the effect of decomposition site and plant litter species on the colonizing microbial communities. For this, litter bag technique using beech and spruce litter was combined with RNA-based fingerprinting and cloning. Litter bags were incubated for 2 and 8 weeks in the Ah horizon of beech and beech–spruce mixed forest sites. Although sugars and starch were rapidly lost, lignin content increased by more than 40% for beech and more than doubled for spruce litter at both soil sites at the end of the experiment. Denaturing gradient gel electrophoresis analysis of 16S and 18S rRNA RT–PCR products was used for screening of differences between bacterial and fungal communities colonizing the two litter types. Development of the microbial community over time was observed to be specific for each litter type and decomposition site. RT–PCR products from both litter types incubated in beech–spruce mixed forest site were also cloned to identify the bacterial and fungal colonizers. The 16S rRNA clone libraries of beech litter were dominated by γ-proteobacterial members, whereas spruce libraries were mainly composed of α-, β-, and γ-proteobacterial members. Ascomycota members dominated the 18S rRNA clone libraries. Clones similar to Zygomycota were absent from spruce, whereas those similar to Basidiomycota and Glomeromycota were absent from beech libraries. Selective effects of litter quality were observed after 8 weeks. The study provides an insight into the bacterial and fungal communities colonizing beech and spruce litter, and the importance of litter quality and decomposition site as key factors in their development and succession.  相似文献   

16.
Soil CO2 evolution rates, soil temperatures and moisture were measured during the dry season in two forest-to-pasture chronosequences in Rondônia, Brazil. The study included pastures ranging from 3 to 80 years-old. Mean dry-season CO2 evolution from the forest in chronosequence 1, 88.8 mg CO2-C m–2h–1 was lower than from the pastures which ranged from 111 to 158 mg CO2-C m–2h–1. We found that temperature was not a good predictor of CO2 emissions from pasture but that there was a significant relationship (r = 0.72,p < 0.05) between soil moisture and pasture emissions. The 13C of the soil CO2 emissions also was measured on chronosequence I; 13C of the CO2 emitted from the C3 forest was –29.43%. Pasture13CO2 values increased from –17.91%. in the 3 year-old pasture to –12.86% in the 80 year-old, reflecting the increasing C4 inputs with pasture age. Even in the youngest (3 year-old) pasture, 70 percent of the CO2 evolved originated from C4 pasture-derived carbon.  相似文献   

17.

Background

The use of wild birds, for several purposes, is directly associated with cultural, ecological, and conservation issues. This study aimed to inventory the wild birds known and used in three communities in Paraíba state, northeast Brazil, and to investigate the sociocultural context in which these activities occur.

Methods

A total of 179 people (98 women and 81 men) were interviewed. Data were collected through free interviews, using semi-structured forms, and posing questions about the use of local wild birds. The species were identified by direct observation of the birds, analysis of photographic records, and the use of a scientific guide.

Results

Each species’ use value (UV) was calculated in three different ways: UVgeneral, UVcurrent, and UVpotential. These UVs ranged from 0.01 to 1.15 for UVg, 0 to 0.21 for UVc, and 0.01 to 1.02 for UVp. A total of 99 species, 81 genera, and 40 families were recorded and classified into the use categories of food, breeding, and medicinal. Thraupidae (12 species), Columbidae, Accipitridae, and Icteridae (8 species each) were the most diverse families.

Conclusions

The use of wild birds is a widespread activity in the studied areas, where many species are used. This demonstrates the need to conduct studies to assess the pressure suffered by these bird species, as well as the need to create public policies that intervene in the use and conservation of wild birds.
  相似文献   

18.
This study investigated rickettsial infection in animals, humans, ticks, and fleas collected in five areas of the state of S?o Paulo. Eight flea species (Adoratopsylla antiquorum antiquorum, Ctenocephalides felis felis, Polygenis atopus, Polygenis rimatus, Polygenis roberti roberti, Polygenis tripus, Rhopalopsyllus lugubris, and Rhopalopsyllus lutzi lutzi), and five tick species (Amblyomma aureolatum, Amblyomma cajennense, Amblyomma dubitatum, Ixodes loricatus, and Rhipicephalus sanguineus) were collected from dogs, cats, and opossums. Rickettsia felis was the only rickettsia found infecting fleas, whereas Rickettsia bellii was the only agent infecting ticks, but no animal or human blood was shown to contain rickettsial DNA. Testing animal and human sera by indirect immunofluorescence assay against four rickettsia antigens (R. rickettsii, R. parkeri, R. felis, and R. bellii), some opossum, dog, horse, and human sera reacted to R. rickettsii with titers at least four-fold higher than to the other three rickettsial antigens. These sera were considered to have a predominant antibody response to R. rickettsii. Using the same criteria, opossum, dog, and horse sera showed predominant antibody response to R. parkeri or a very closely related genotype. Our serological results suggest that both R. rickettsii and R. parkeri infected animals and/or humans in the studied areas.  相似文献   

19.
We analyzed, by env and gag heteroduplex mobility assay, 149 human immunodeficiency virus (HIV-1) positive samples collected in Ceará during the year 2000. The prevalence of subtype B was 81.2% and the prevalence of subtype F and B/F recombinants were both 2.7%. Eight (5.4%) and 12 (8%) out of 149 samples showed indeterminate results in the env and gag analysis respectively. By FokI restriction fragment length polymorphism, 34% of the subtype B samples were identified as the typical Brazilian subtype B.In the present study, we identified HIV-1 subtype F and B/F in Ceará for the first time. Our results contribute to the understanding of HIV in Brazil, and may prove useful for the development of vaccine candidates.  相似文献   

20.
The relationship between algal communities’ species diversity and the catchment of rivers in the southern Russian Far East has been studied. The number of species, varieties, and forms of algae increased significantly according to the increase in the head river area up to 80–100 km2; then this number slowed down dramatically. In general, the relationship between the number of algal taxa (D) and the catchment of the river (S, km2) was described as D = 91.6S 0.194 (R 2 = 0.97).  相似文献   

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